1 2 /* 3 * Copyright 2012 Google Inc. 4 * 5 * Use of this source code is governed by a BSD-style license that can be 6 * found in the LICENSE file. 7 */ 8 9 #ifndef SkGradientShaderPriv_DEFINED 10 #define SkGradientShaderPriv_DEFINED 11 12 #include "SkGradientShader.h" 13 #include "SkClampRange.h" 14 #include "SkColorPriv.h" 15 #include "SkFlattenableBuffers.h" 16 #include "SkMallocPixelRef.h" 17 #include "SkUnitMapper.h" 18 #include "SkUtils.h" 19 #include "SkTemplates.h" 20 #include "SkBitmapCache.h" 21 #include "SkShader.h" 22 23 #ifndef SK_DISABLE_DITHER_32BIT_GRADIENT 24 #define USE_DITHER_32BIT_GRADIENT 25 #endif 26 27 static inline void sk_memset32_dither(uint32_t dst[], uint32_t v0, uint32_t v1, 28 int count) { 29 if (count > 0) { 30 if (v0 == v1) { 31 sk_memset32(dst, v0, count); 32 } else { 33 int pairs = count >> 1; 34 for (int i = 0; i < pairs; i++) { 35 *dst++ = v0; 36 *dst++ = v1; 37 } 38 if (count & 1) { 39 *dst = v0; 40 } 41 } 42 } 43 } 44 45 // Clamp 46 47 static inline SkFixed clamp_tileproc(SkFixed x) { 48 return SkClampMax(x, 0xFFFF); 49 } 50 51 // Repeat 52 53 static inline SkFixed repeat_tileproc(SkFixed x) { 54 return x & 0xFFFF; 55 } 56 57 // Mirror 58 59 // Visual Studio 2010 (MSC_VER=1600) optimizes bit-shift code incorrectly. 60 // See http://code.google.com/p/skia/issues/detail?id=472 61 #if defined(_MSC_VER) && (_MSC_VER >= 1600) 62 #pragma optimize("", off) 63 #endif 64 65 static inline SkFixed mirror_tileproc(SkFixed x) { 66 int s = x << 15 >> 31; 67 return (x ^ s) & 0xFFFF; 68 } 69 70 #if defined(_MSC_VER) && (_MSC_VER >= 1600) 71 #pragma optimize("", on) 72 #endif 73 74 /////////////////////////////////////////////////////////////////////////////// 75 76 typedef SkFixed (*TileProc)(SkFixed); 77 78 /////////////////////////////////////////////////////////////////////////////// 79 80 static const TileProc gTileProcs[] = { 81 clamp_tileproc, 82 repeat_tileproc, 83 mirror_tileproc 84 }; 85 86 /////////////////////////////////////////////////////////////////////////////// 87 88 class SkGradientShaderBase : public SkShader { 89 public: 90 SkGradientShaderBase(const SkColor colors[], const SkScalar pos[], 91 int colorCount, SkShader::TileMode mode, SkUnitMapper* mapper); 92 virtual ~SkGradientShaderBase(); 93 94 virtual bool setContext(const SkBitmap&, const SkPaint&, const SkMatrix&) SK_OVERRIDE; 95 virtual uint32_t getFlags() SK_OVERRIDE { return fFlags; } 96 virtual bool isOpaque() const SK_OVERRIDE; 97 98 void getGradientTableBitmap(SkBitmap*) const; 99 100 enum { 101 /// Seems like enough for visual accuracy. TODO: if pos[] deserves 102 /// it, use a larger cache. 103 kCache16Bits = 8, 104 kCache16Count = (1 << kCache16Bits), 105 kCache16Shift = 16 - kCache16Bits, 106 kSqrt16Shift = 8 - kCache16Bits, 107 108 /// Seems like enough for visual accuracy. TODO: if pos[] deserves 109 /// it, use a larger cache. 110 kCache32Bits = 8, 111 kCache32Count = (1 << kCache32Bits), 112 kCache32Shift = 16 - kCache32Bits, 113 kSqrt32Shift = 8 - kCache32Bits, 114 115 /// This value is used to *read* the dither cache; it may be 0 116 /// if dithering is disabled. 117 #ifdef USE_DITHER_32BIT_GRADIENT 118 kDitherStride32 = kCache32Count, 119 #else 120 kDitherStride32 = 0, 121 #endif 122 kDitherStride16 = kCache16Count, 123 }; 124 125 126 protected: 127 SkGradientShaderBase(SkFlattenableReadBuffer& ); 128 virtual void flatten(SkFlattenableWriteBuffer&) const SK_OVERRIDE; 129 SK_DEVELOPER_TO_STRING() 130 131 SkUnitMapper* fMapper; 132 SkMatrix fPtsToUnit; // set by subclass 133 SkMatrix fDstToIndex; 134 SkMatrix::MapXYProc fDstToIndexProc; 135 TileMode fTileMode; 136 TileProc fTileProc; 137 int fColorCount; 138 uint8_t fDstToIndexClass; 139 uint8_t fFlags; 140 141 struct Rec { 142 SkFixed fPos; // 0...1 143 uint32_t fScale; // (1 << 24) / range 144 }; 145 Rec* fRecs; 146 147 const uint16_t* getCache16() const; 148 const SkPMColor* getCache32() const; 149 150 void commonAsAGradient(GradientInfo*) const; 151 152 private: 153 enum { 154 kColorStorageCount = 4, // more than this many colors, and we'll use sk_malloc for the space 155 156 kStorageSize = kColorStorageCount * (sizeof(SkColor) + sizeof(Rec)) 157 }; 158 SkColor fStorage[(kStorageSize + 3) >> 2]; 159 SkColor* fOrigColors; // original colors, before modulation by paint in setContext 160 bool fColorsAreOpaque; 161 162 mutable uint16_t* fCache16; // working ptr. If this is NULL, we need to recompute the cache values 163 mutable SkPMColor* fCache32; // working ptr. If this is NULL, we need to recompute the cache values 164 165 mutable uint16_t* fCache16Storage; // storage for fCache16, allocated on demand 166 mutable SkMallocPixelRef* fCache32PixelRef; 167 mutable unsigned fCacheAlpha; // the alpha value we used when we computed the cache. larger than 8bits so we can store uninitialized value 168 169 static void Build16bitCache(uint16_t[], SkColor c0, SkColor c1, int count); 170 static void Build32bitCache(SkPMColor[], SkColor c0, SkColor c1, int count, 171 U8CPU alpha); 172 void setCacheAlpha(U8CPU alpha) const; 173 void initCommon(); 174 175 typedef SkShader INHERITED; 176 }; 177 178 static inline int init_dither_toggle(int x, int y) { 179 return ((x ^ y) & 1) * SkGradientShaderBase::kDitherStride32; 180 } 181 182 static inline int next_dither_toggle(int toggle) { 183 return toggle ^ SkGradientShaderBase::kDitherStride32; 184 } 185 186 static inline int init_dither_toggle16(int x, int y) { 187 return ((x ^ y) & 1) * SkGradientShaderBase::kDitherStride16; 188 } 189 190 static inline int next_dither_toggle16(int toggle) { 191 return toggle ^ SkGradientShaderBase::kDitherStride16; 192 } 193 194 /////////////////////////////////////////////////////////////////////////////// 195 196 #if SK_SUPPORT_GPU 197 198 #include "gl/GrGLEffect.h" 199 #include "gl/GrGLEffectMatrix.h" 200 201 class GrEffectStage; 202 class GrBackendEffectFactory; 203 204 /* 205 * The interpretation of the texture matrix depends on the sample mode. The 206 * texture matrix is applied both when the texture coordinates are explicit 207 * and when vertex positions are used as texture coordinates. In the latter 208 * case the texture matrix is applied to the pre-view-matrix position 209 * values. 210 * 211 * Normal SampleMode 212 * The post-matrix texture coordinates are in normalize space with (0,0) at 213 * the top-left and (1,1) at the bottom right. 214 * RadialGradient 215 * The matrix specifies the radial gradient parameters. 216 * (0,0) in the post-matrix space is center of the radial gradient. 217 * Radial2Gradient 218 * Matrix transforms to space where first circle is centered at the 219 * origin. The second circle will be centered (x, 0) where x may be 220 * 0 and is provided by setRadial2Params. The post-matrix space is 221 * normalized such that 1 is the second radius - first radius. 222 * SweepGradient 223 * The angle from the origin of texture coordinates in post-matrix space 224 * determines the gradient value. 225 */ 226 227 class GrTextureStripAtlas; 228 229 // Base class for Gr gradient effects 230 class GrGradientEffect : public GrEffect { 231 public: 232 233 GrGradientEffect(GrContext* ctx, 234 const SkGradientShaderBase& shader, 235 const SkMatrix& matrix, 236 SkShader::TileMode tileMode); 237 238 virtual ~GrGradientEffect(); 239 240 bool useAtlas() const { return SkToBool(-1 != fRow); } 241 SkScalar getYCoord() const { return fYCoord; }; 242 const SkMatrix& getMatrix() const { return fMatrix;} 243 244 virtual void getConstantColorComponents(GrColor* color, uint32_t* validFlags) const SK_OVERRIDE; 245 246 protected: 247 248 /** Populates a pair of arrays with colors and stop info to construct a random gradient. 249 The function decides whether stop values should be used or not. The return value indicates 250 the number of colors, which will be capped by kMaxRandomGradientColors. colors should be 251 sized to be at least kMaxRandomGradientColors. stops is a pointer to an array of at least 252 size kMaxRandomGradientColors. It may be updated to NULL, indicating that NULL should be 253 passed to the gradient factory rather than the array. 254 */ 255 static const int kMaxRandomGradientColors = 4; 256 static int RandomGradientParams(SkRandom* r, 257 SkColor colors[kMaxRandomGradientColors], 258 SkScalar** stops, 259 SkShader::TileMode* tm); 260 261 virtual bool onIsEqual(const GrEffect& effect) const SK_OVERRIDE; 262 263 private: 264 265 GrTextureAccess fTextureAccess; 266 SkScalar fYCoord; 267 GrTextureStripAtlas* fAtlas; 268 int fRow; 269 SkMatrix fMatrix; 270 bool fIsOpaque; 271 272 typedef GrEffect INHERITED; 273 274 }; 275 276 /////////////////////////////////////////////////////////////////////////////// 277 278 // Base class for GL gradient effects 279 class GrGLGradientEffect : public GrGLEffect { 280 public: 281 GrGLGradientEffect(const GrBackendEffectFactory& factory); 282 virtual ~GrGLGradientEffect(); 283 284 virtual void setData(const GrGLUniformManager&, const GrEffectStage&) SK_OVERRIDE; 285 286 protected: 287 /** 288 * Subclasses must reserve the lower kMatrixKeyBitCnt of their key for use by 289 * GrGLGradientEffect. 290 */ 291 enum { 292 kMatrixKeyBitCnt = GrGLEffectMatrix::kKeyBits, 293 kMatrixKeyMask = (1 << kMatrixKeyBitCnt) - 1, 294 }; 295 296 /** 297 * Subclasses must call this. It will return a value restricted to the lower kMatrixKeyBitCnt 298 * bits. 299 */ 300 static EffectKey GenMatrixKey(const GrEffectStage& s); 301 302 /** 303 * Inserts code to implement the GrGradientEffect's matrix. This should be called before a 304 * subclass emits its own code. The name of the 2D coords is output via fsCoordName and already 305 * incorporates any perspective division. The caller can also optionally retrieve the name of 306 * the varying inserted in the VS and its type, which may be either vec2f or vec3f depending 307 * upon whether the matrix has perspective or not. It is not necessary to mask the key before 308 * calling. 309 */ 310 void setupMatrix(GrGLShaderBuilder* builder, 311 EffectKey key, 312 const char* vertexCoords, 313 const char** fsCoordName, 314 const char** vsVaryingName = NULL, 315 GrSLType* vsVaryingType = NULL); 316 317 // Emits the uniform used as the y-coord to texture samples in derived classes. Subclasses 318 // should call this method from their emitCode(). 319 void emitYCoordUniform(GrGLShaderBuilder* builder); 320 321 // emit code that gets a fragment's color from an expression for t; for now this always uses the 322 // texture, but for simpler cases we'll be able to lerp. Subclasses should call this method from 323 // their emitCode(). 324 void emitColorLookup(GrGLShaderBuilder* builder, 325 const char* gradientTValue, 326 const char* outputColor, 327 const char* inputColor, 328 const GrGLShaderBuilder::TextureSampler&); 329 330 private: 331 SkScalar fCachedYCoord; 332 GrGLUniformManager::UniformHandle fFSYUni; 333 GrGLEffectMatrix fEffectMatrix; 334 335 typedef GrGLEffect INHERITED; 336 }; 337 338 #endif 339 340 #endif 341